The clarification of mechanisms involved in cell differentiation represents a major problem. Due to the complexity of the organization of higher (eukaryotic) cells, model systems for differentiation studies have been sought in lower (prokaryotic) cells. One such system which is proving to be an excellent model is that of bacterial sporulation and germination. The germination system is a defined system that can be made synchronous and the direction of development is easily manipulated. One such manipulation is that of causing an outgrowing cell to form a spore without first going through an intervening symmetrical cell division (microcycle sporulation). We have developed a system using microcycle sporulation to study the processes of sporulation induction. Our approaches to this problem are based on our hypothesis that the initial developmental sequences leading to spore formation represent a modified cell division with the division septum being constructed in an asymmetrical position in the cell. It is our aim to investigate the mechanism(s) involved in asymmetrical versus symmetrical division. The probes outlined in this proposal are directed towards gaining such information. We will investigate the relationship between the DNA cycle and sporulation induction. Specifically we are asking what role does the chromosome have in septum formation. It is suggested that elongation of bacilli is achieved by growth from a specific membrane growth site. We are interested in relating the development of such a growth site both to asymmetrical and symmetrical division.